Soil tilling device



Sept. 8, 1959 l. KAMLUKIN son. TILLINGDEVICE.

Filed yJune 1o, 1957 4 Sheets-Sheet 1 Sept. 8, 1959 l. KAMLUKIN sonTILLING DEVICE 4 Sheets-Sheet 2 Filed June l0, 1957 Sept. 8, 1959 l.KAMLUKIN SOIL TILLING DEVICE 4 Sheets-Sheet 3 Fi1ed-June 10, 1957 ffm"Kim/Mm Sept. 8, 1959 Filed-June l l. KAMLUKIN SOIL TILLING DEVICE 4Sheets-Sheet 4 United States Patent O SOIL TILLING DEVICE Igor Kamlukin,Milwaukee, Wis., assignor to Simplicity Manufacturing Company, PortWashington, Wis., a corporation of Wisconsin Application June f10, 1957,Serial No. 664,775

9 Claims. (Cl. 1172-42) This invention relates to soil tilling devicesand has more particul-ar reference to small gardening apparatus of thetype having a power driven rotor which serves as the traction means bywhich the tilling device is propelled and has tines thereon to till thesoil `as the device travels along the ground.

In general, it is the object of this invention to provide improved meansfor transmitting driving torque from the internal combustion enginecommonly used on soil tilling devices of the character described, to therotor of the device.

More specifically, it is an object of this invention to providereversing transmission means for a soil tilling device of the characterdescribed through which the rotor of the device may be readily driveneither forwardly or in the reverse direction from the internalcombustion engine so as to facilitate maneuvering of the device in closequarters.

Still another object of this invention resides in the provision ofunusually simple and inexpensive but reliable transmis-sion meansfeaturing a reversing belt arrangement which is especially well suitedfor use on small power driven gardening implements such as soil tillingapparatus or the like.

A further object of this invention resides in the provision of a rotarysoil tilling device of the character described having a power sourcewhich comprises a vertical shaft engine, and featuring an unusuallycompact and well protected belt type transmission for drivinglyconnecting the engine with the rotor of the device.

With the above and other objects in view which will appear as thedescription proceed-s, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate two complete examples of thephysical embodiments of the invention constructed according to the bestmodes so far devised for the practical application of the principlesthereof, and in which:

Figure l is a side elevational view of a soil tilling device embodyingthe principles of this invention;

Figure 2 is an enlarged horizontal sectional view taken through Figure lalong the plane of the line 2-2, and illustrating the reversing belttransmission of this invention;

Figure 3 is a vertical sectional view taken through Figure 2 along theline 3 3;

Figure 4 is a View partly in rear elevation and partly in section takenalong the line 4 4 in Figure 1;

Figure 5 is a fragmentary sectional view of a portion of thetransmission means taken along the line 5-5 in Figure 2;

Figure 6 is a more or less diagrammatic view illustrating the manualcontrol means for shifting the transmisrice sion out of neutral toeither of its two operative positions; and

Figure 7 is a more or less diagrammatic view on the order of Figure 2but illustrating a modified embodiment of the transmission.

Referring now more particularly to the yaccompanying drawings in whichlike reference characters have been applied to like parts throughout theseveral views, the numeral 10 generally designates a rotary soil tillingdevice of a small size, especially rnseful for gardening. The device isprovided with a chassis 11 supported by a rotor 12 driven from aninternal combustion engine 13 mounted on the chassis above andrearwardly of the rotor. The rotor revolves on a transverse axis andcarries a number of tines terminating in hoe-like members 14 which areshaped and arranged to dig into and till the soil as the rotor revolvesin the counterclockwise direction as seen in Figure l. When the rotorrevolves in the clockwise direction the hoe-like members act to lift therotor up onto the tilled soil and propel the device rearward.

The main components of the chassis comprise a substantially shallowhorizontal transmission housing 16 which is elongated in thelongitudinal dimension of the device, and an elongated vertical bearing17 secured to the underside of the transmission housing at its front.The rotor shaft -18 is rotatably journaled on the lower end portion ofthe vertical bearing 17. As will be appreciated, the tine-carrying rotor12 not only effects tilling of the soil as the rotor revolves in saidcounterclockwise direction but it also serves as traction means tosupport the chassis and to propel the tilling device along the groundbeing worked.

A depth or drag bar 20 pivotally supported as at 22 between a pair oftransversely opposite arms 21 secured to and projecting from the rearportion of the transmission housing controls the depth to which thetines 14 on the rotor work the soil and, of course, is adjustable up anddown to enable the rotor to till the soil to different depths. In itsoperative position shown in Figure l, this depth or drag bar is rigidlysupported by an abutment 21' fixed to the arms 21 against rearwarddisplacement of its lower end s0 that by dragging in the ground itresists forward propulsion of the soil tilling device by the rotor 12and in so doing coacts with the rotor to effect the desired tilling. Thedepth to which the rotor digs itself into the ground and thus the depthto which the soil is tilled or cultivated depends upon the elfectivenesswith which the depth or drag bar resists forward propulsion of thedevice and this in turn depends upon the extent the bar projects downinto the ground.

The mounting of the depth or drag bar upon the arms 21, though itprevents rearward displacement of its lower ground engaging end, is suchthat upon retraction, that is, rearward movement of the device, the baris free to swing out of the ground and become inelective to resist suchrearward movement of the device. Accordingly, the depth of drag barcooperates with the rotor 12 to effect tilling or cultivating of thesoil as the device moves forward and by being free to have its lower endswing forward, it does not interfere with quick retraction of the deviceby reverse rotation of the rotor. Also, as will be readily understoodthe bar may be raised from its operative position shown in Figure l andsecured in a higher position by removal and replacement of its pivot pin22 to facilitate transportation of the tilling apparatus from place toplace.

To further facilitate such transportation of the apparatus, it isprovided with a pair of rubber tired wheels 24 supported from the rearof the transmission housing for rotation on a transverse axis 25 bymeans of a pair of transversely opposite arms 26 connected to the rearportion of the chassis. These arms mount the wheels` 24 substantiallymidway between the rotor 12 and the depth bar 20.

The transmission housing :16, which may be a sheet metal stamping, isformed with a cover 28 which also serves as a substantially horizontalengine supporting platform located on the rear portion of thetransmission housing. The platform 28 thus mounts the internalcombustion engine 13 above yand rearwardly of the rotor 12, in aposition'which is desirable from the standpoint of weight Idistributionduring tilling.

The engine 13 is of the vertical shaft single cylinder type, and itscrankshaft 30 projects downwardly therefrom through a siutable aperturein the engine supporting platform 28 into the rear portion of thetransmission housing. The engine also has a camshaft 31, however, whichlikewise projects downwardly from the engine through a suitable hole inthe supporting platform 28 and into the rear portion of the transmissionhousing, in laterally spaced relation to the crankshaft. The crankshaft30 and the camshaft 31, therefore, may be considered to provide twopower driven shafts which rotate in opposite directions on transverselyspaced vertical axes and have their outer or lower end portions disposedin the rear of the transmission housing.

The rotor 12 which is to be driven from the engine is provided with adrive shaft 33 journaled in the elongated bearing 17 for rotation on avertical axis at the front of the chassis, and at its lower end havingthe usual worm and worm wheel driving connection with the rotor (notshown). The upper end of the drive shaft projects out of the bearing 17and into the forward end portion of the transmission housing 16 so as tobe spaced from but forwardly opposite the lower end portions of thecrankshaft and camshaft of the engine.

The transmission means 35 of this invention features a reversing beltarrangement, and is adapted to drivingly connect the rotor 12 with theinternal combustion engine for rotation in opposite directions. For thispurpose, the upper end portion of the rotor drive shaft 33 whichprojects into the transmission housing has a pair of upper and lower Vpulleys 36 and 37, respectively, secured thereto. The upper pulley 36 onthe rotor drive shaft occupies a position which is substantially inhorizontal `alignment with a cooperating V pulley 38 fixed on the lowerend of the camshaft, and the lower pulley 37 on the rotor drive shaftoccupies a position substantially in horizontal alignment with acooperating V pulley 33 on the lower end portion of the crankshaft.

A single loop forward belt 40 is trained around the cooperating pulleys37 and 39 and normally loosely encircles these pulleys so as to precludethe transmission of driving torque from the crankshaft to the rotordrive shaft, except upon tightening of the belt. When tightened intodriving engagement with the pulleys 37 and 39, the forward belt isadapted to transmit rotation from the engine to the rotor drive shaftfor rotation of the rotor 12 in a forward direction, which iscounterclockwise as seen in Figure 1, such that the tines 14 on therotor operate to till the soil and to propel the tilling deviceforwardly along the ground being tilled.

A single loop reverse belt 41 is similarly loosely trained about theupper pulley 36 on the rotor drive shaft and its cooperating pulley 38on the lower end portion of the camshaft, so as to normally preclude thetransmission of driving torque from the cam shaft to the rotor driveshaft. When tightened into driving engagement with the pulleys 36 and38, however, the reverse drive belt 41 transmits rotation from thecamshaft to the rotor drive shaft in the opposite direction, namelyclockwise as viewed in Figure l, so as to thereby establish a reversedriving connection between the engine and the rotor operable to causethe tilling device to back up and thus facilitate maneuvering of thedevice in close quarters.

The reversing transmission 35 of this invention further includes a belttightening device 43 by which the operator of the device may selectivelytighten the forward and reverse belts 40-41 into driving engagement withthe pulleys about which they are trained. In the present case the belttightening device 43 is in the form of a lever 44 having its hub 45journaled on a bearing 46 carried by the bottom wall 47 of thetransmission housing, for rotation in opposite directions coaxially ofthe rotor drive shaft 33. As seen best in Figure 5, the hub 45 of thelever is located beneath the lower pully 37 on the rotor drive shaft,and the lever is further provided with a pair of laterally spaced arms48 and 49 which project rearwardly, one toward the camshaft and theother toward the crankshaft. At its outer end the arm 48 carries avertical stud 50 upon which a roller 51 is freely rotatably mounted,substantially forwardly opposite the axis of the camshaft 31 and to oneside of both stretches of the forward belt 40 but in position to engagethe exterior surface of that stretch of the forward belt which isadjacent to the camshaft. In the neutral position of the `belttightening device shown in Figures 2 and 6, the roller 5t) lightlyengages the adjacent stretch of the forward driving belt and holds itdeflected toward a plane containing the axes of the rotor drive shaftand the crankshaft but not tightly enough engaged with the pulleys 37and 39 on said shafts as to establish a driving connection between them.

A vertical stud 52 xed in the outer end of the arm 49 of the belttightening device freely rotatably mounts a similar roller 53,substantially forwardly opposite the axis of the crankshaft and to oneside of both stretches of the reverse belt 41 but in position tonormally lightly engage the exterior of that stretch of the reversedrive belt 41 which is adjacent to the crankshaft. In the neutralposition of the belt tightening device 43 shown in Figures 2 and 6,therefore, the rollers 51 and 53, which may be called freely rotatableidlers, engage their respective belts with substantially light forcewhich is insufficient to establish a driving connection between eitherthe crankshaft or the camshaft and the rotor drive shaft 33.

The transmission of driving torque from the crankshaft to the rotordrive shaft and consequently to the rotor for forward operation of thetilling device is effected by swinging the belt tightening device 43' onits bearing in a counterclockwise direction as seen in Figures 2 and 6,out of its neutral position therein shown. Such swinging motion of thebelt tightening device further slackens the condition of the reversedrive belt 41 about pulleys 36 and 38 and tightens the forward drivebelt 4th into driving engagement with its pulleys 37 and 39, so that therotor drive shaft rotates with and in the same direction as the enginecrankshaft. Inasmuch as the engine camshaft rotates in a directionopposite to that of the crankshaft, the drive to the rotor may bereversed, causing the tilling device to back up, merely by swinging thebelt tightening device 43 in a clockwise direction out of its neutralposition shown to a position such that the forward drive belt `isfurther slackened and the reverse drive belt 41 is tightened by theidler 53 into driving engagement with its pulleys 36 and 38. Thisdrivingly connects the rotor drive shaft with the camshaft of theengine.

Swinging motion may be manually imparted to the belt tightening deviceto shift it from its neutral position to either its forward or reversedrive positions by means of a link 55 in the form of a rod having oneend connected to a lug as at 56 on one side of the hub of the belttightening device. This link extends horizontally rearwardly through thetransmission housing along one upright side wall thereof, and its rearportion is slidably received in an apertured clip 57 secured to saidside wall at the rear of the housing. The belt tightening device and theclip 57, therefore, serve to constrain the link to endwise fore and aftmotion relative to the transmission housing. Rearward motion of the link55, of course, swings the belt tightening device counterclockwise to itsforward drive position, and forward motion of the link swings the belttightening device clockwise to its reverse drive position. j i

Such endwise fore and aft motion is manually imparted to the link 55through an elongated control rod 59 supported jointly by the rear endportion ofthe link and by the grip portion 61 on one of a pair oftransversely opposite handle bars 62 joined to and extending upwardlyand rearwardly from the rear of the chassis. The lower end of thecontrol rod is pivotally connected to the rear of the link as at 63, andthe rod extends upwardly and rearwardly alongside the adjacent handlebar 62 at a slightly divergent angle with respect thereto so that itsupper end portion crosses the grip portion 61 on said handle bar. Ashifter knob 64 on the upper end of the control rod, above the gripportion 61, facilitates the application of downward force on the rod andenables the operator to hold the rod in a downwardly shifted position atwhich the transmission is in reverse operation.

The upper end portion of the control rod is slidingly and guidinglyreceived in a clip 65 mounted on a cross pin 66 through the adjacentgrip portion 61 of the handle bar for swiveling motion about ahorizontal axis, the clip thus cooperating with the rear end portion ofthe link 55 to more or less constrain the control rod to endwise up anddown motion relative to the handle bars out of the neutral positionthereof shown in solid lines in Figures l and 6. The pivot pin 66 alsoserves to pivotally mount a control lever 67 on the grip portion 61, andfor this purpose the hub portion 68 of the lever is bifurcated tostraddle the grip portion and to receive the pin 66. The control leveris mounted on the grip portion with the arm of the lever beneath thegrip portion of the handle bar and diverging with respect thereto towardthe rear extremity of the grip portion.

The purpose of the control lever 67 is to enable the operator to readilyimpart upward endwise motion to the control rod so as to shift thetransmission into forward drive position, and the operator must manuallyhold the control lever in an actuated position during all forwardoperation of the tilling device. The motion transmitting connectionbetween the control lever 67 and the control rod comprises a tensionspring 70 having one end connected to the control lever as at 71intermediate the pivoted and free ends of the lever, and having itsother end connected to a clip 72 on the control rod a distance beneaththe pivot axis of the control lever.

The control lever is so located on the grip portion 61 of the handle barthat the operator may conveniently grasp both the grip portion and thecontrol lever with the same hand, and swing the control lever 67upwardly into lateral juxtaposition with the grip portion. When soactuated, the tension spring 70 is stretched by the lever and pulls the4control rod upwardly in its guide clip 65 to actuate the link 55 to therear, causing the reverse drive belt 41 to be further slackened and theforward drive belt 40 to be tightened into dr-iving engagement with thecrankshaft pulley 39 and the pulley 37 on the rotor drive shaft. If forany reason the operator releases his grip upon the control lever 67, thebelt tightening device automatically returns to its neutral positiondisrupting the driving connection between the engine and the rotor underthe combined inliuence of the weight of the control rod and the pressureexerted by the forward belt 40 on its idler 51.

If the operator desires to run the tilling device rearwardly, inreverse, it is only necessary for him to push downwardly upon the knob64 on the upper end of the control rod to slide the link 55 forwardlyand thus actuate the belt tightening device in a clockwise direction asviewed in Figure 2 to establish the driving connection between theengine camshaft and the rotor drive shaft. In this case also theoperator of the device must hold the control rod in its downwardlyactuated position as long as he wishes to maintain the reverse drivingconnection to the rotor 12. As soon as the operator releases the `6 knob64 on the upper end of the control rod the tension spring 70 lifts therod upwardly and returns it to its neutral position, at the same timereturning the belt tightening device to its neutral position. The spring70 is aided in this latter instance by the force which the reverse belt41 exerts upon its idler 53.

In this connection also, it should be observed that the control lever 67is supported on the pivot pin 66 for swinging motion between denedlimits. The limit of counterclockwise swinging motion is defined by theengagement of the arm of the lever with the underside of the gripportion 61 on the handle bar, and the limit of clockwise motion of thecontrol lever is defined by the engagement between the grip portion 61and a shoulder 74 on the hub end of the lever, at the junction of thearm with the bifurcated hub portion of the lever.

While the reversing transmission described depends upon the provision ofa pair of oppositely driven power shafts, such as the crankshaft and thecamshaft of an internal combustion engine preferably mounted with itsshafts vertical to achieve the compactness which characterizes thetilling device of this invention, it is also possible to provide asimple and entirely satisfactory reversing belt transmission which canbe used with an engine having only its crankshaft projecting to theexterior thereof to provide a single power shaft for connection to therotor drive shaft. A reversing transmission of this type is more or lessdiagrammatically illustrated in Figure 7, which view substantiallycorresponds to Figure 2 of the previous embodiment of the invention.

As shown in Figure 7, the single power shaft 75, which may be providedby the crankshaft of an internal combustion engine, rotates on an axiswhich is spaced a fixed distance from and parallel to the axis of therotor drive shaft 33. In this case also the rotor drive shaft hasforward and reverse pulleys 76 and 77 respectively, fixed thereto withthe reverse pulley uppermost, and each aligning with one of a pair offorward and reverse pulleys 78 and 79 fixed on the engine crankshaft.

A forward drive belt 81 is trained about the forward pulley 7S on thecrankshaft and the lower pulley 76 on the rotor drive shaft, as a singleloop encircling these pulleys and normally loosely trained thereover. Areverse drive belt 82 is trained about the reverse pulley 79 on thecrankshaft and the upper pulley 77 on the rotor drive shaft, with itsstretches crossing one another as illustrated, and defining a pair ofloops each encircling one of the pulleys 77-79, and normally looselytrained thereover.

Thus it will be seen that when the forward drive belt 81 is tightenedinto driving engagement with its pulleys 76 and 78, it connects therotor drive shaft with the crankshaft for rotation therewith in the samedirection as the crankshaft rotates. However, when the crossed reversedrive belt 82 is tightened into driving engagement with its pulleys 77and 79, it establishes a driving connection between the rotor driveshaft and the crankshaft by which the rotor drive shaft is constrainedto rotate with the crankshaft but in a direction opposite to that inwhich the crankshaft rotates.

A belt tightening device or lever generally designated 84 is alsoprovided for this embodiment of the invention, to enable selectivetightening of the forward and reverse drive belts. The belt tighteninglever is rnedially pivoted alongside the crankshaft, to swing on a stud85, the axis of which is in iixed spaced apart relation to that of thecrankshaft and parallel thereto. One arm 86 of the lever extendsoutwardly from the pivoted hub portion thereof, forwardly of the pulleyson the crankshaft. A pair of free running idlers, one in the form of aroller 87 and the other in the form of a V pulley 88 is freely rotatablyjournaled on a stud 89 fixed in the outer end portion of the arm 86,with the roller 87 located entirely to one side of both stretches of theforward drive belt 81 and normally lightly engaging the outer surface ofthe adjacent stretch thereof, and with the idler pulley 88 inside thatloop of the reverse drive belt 82 which encircles the pulley 79 on thecrankshaft where it lightly bears upon the inner sln'face of theadjacent stretch of the loop.

Consequently if the belt tightening lever is swung in a counterclockwisedirection about its pivot 85, out of the neutral position of the levershown, it further slackens the reverse drive belt and at the same `timetightens the forward drive belt 81 about the engine pulley 78 and thepulley 76 on the rotor drive shaft to establish a forward drivingconnection to vthe latter whereby the rotor shaft rotates in the samedirection as the crankshaft. If the belt tightening lever is swung in aclockwise direction out of the neutral position shown, it furtherslackens the forward drive belt and tightens the reverse drive belt 82about the engine pulley 79 and the pulley 77 on the rotor drive shaft tocause rotation of the rotor `dri've shaft in the opposite direction, orcounter to the rotation of the crankshaft.

The other arm 90 of the belt tightening lever extends laterallyoutwardly from the hub portion of the lever, away from the crankshaft,and it has an apertured outer end to receive one end portion of a link91 similar to the link S of the previous embodiment of the invention.The link 91 may be in the form of a rod having a threaded end portion toreceive clamping nuts 92 thereon which may be tightened against theopposite sides of the outer end portion of the arm 90 of the belttightening lever to securely connect the link thereto. The belttightening lever 84 may be swung from its neutral position shown toeither of its two operative positions in a manner similar to thatdescribed previously, namely by means of a control rod 69' having itslower end connected to the rear of the link 91 as at 63.

From the foregoing description taken together with the accompanyingdrawings, it will be readily apparent to those skilled in the art thatthis invention provides a soil tilling device which features compactnessand which by reason of its novel reversing transmission greatlyfacilitates maneuvering of the device in close quarters; and wherein thereversing belt transmission itself features simplicity and low costwithout sacrificing reliability of the transmission.

What I claim as my invention is:

l. In a power driven hand guided soil tilling device, the combinationof: a chassis frame having handle means by which the device may beguided by an attendant; a cultivating rotor jo-urnaled on the frame withits axis horizontal and transverse to the frame, said rotor havinghoe-like tines, hoe means on the ends of said tines shaped to dig intoand till the soil as a consequence of rotation of the rotor in a forwarddirection as long as the device does not move forwardly across theground at the rate forward rotation of the rotor tends to move it, andto lift the rotor up onto the surface of the tilled soil as aconsequence of retrograde rotation of the rotor, said rotor being theentire traction means for the device and at all times that it is driventending to propel the device forwardly or rearwardly depending upon thedirection in which the rotor is being driven; ground engaging meansoperable to resist forward propulsion of the device by the rotor andthus cause the rotor tines to dig into and effect tilling of the soil;means mounting said ground engaging means on the chassis frame in amanner holding the same effective to resist forward motion of the devicebut ineffective to resist rearward motion thereof so that the device isat all times unrestrictedly free to be propelled rearward by reverserotation of the rotor; a prime mover carried by the chassis frame; areversing drive transmission means carried by the frame to drive therotor from the prime mover in one direction or the other and therebyprovide for forward tilling propulsion of the device or rearwardnon-tilling propulsion thereof over the tilled soil, said reversingdrive transmission means including shiftable control means mounted formotion from a neutral position, at which said control means renders thetransmission means ineffective to transmit torque to the rotor,selectively to either of two operating positions at one of which thecontrolemeans activates the transmlssion means to ydrivingly connect theprime mover with the rotor `to produce forward rotation of the rotor,and in the other of which said control means activates the transmissionmeans to drivingly connect the prime mover with the rotor to produceretrograde rotation of the rotor; and manually operable means on thedevice, connected in motion transmitting relation with said controlmeans, and readily accessible to an attendant of the device, formanually shifting said control means from one to another of lsaidpositions thereof, whereby either the forward or rearward propulsion ofthe device by the rotor may be substantially instantaneously halted andthe device operated in the opposite `direction at the lwill of theattendant.

2. In a power driven hand-guided soil tilling device, the combinationset forth in claim l, further characterized by the provision of: ashallow substantially horizontal housing which provides substantiallythe entire chassis frame and has the drive transmission means containedtherein; and by the fact that the prime mover is an internal combustionengine mounted on top of said housing and having a power shaftprojecting downwardly into the housing for cooperation with thetransmission means.

3. In a power driven hand-guided soil tilling device, the combinationset forth in claim l further characterized by the fact that thereversing drive transmission means comprises two spaced pairs of axiallyadjacent pulleys, one pair being drivingly connected with the rotor andthe other pair being drivingly connected with the prime mover, beltsnormally loosely connecting one pulley of each pair with a pulley of theother pair, the stretches of one of said belts defining a single looparound its pulleys and the stretches of the other belt crossing oneanother and defining a pair of loops each encircling one of the pulleysabout which said other belt is trained, and a pair of idlers, one foreach belt, and means mounting the idlers for free rotation and forbodily movement together in opposite directions from a neutral positionat which both belts are loose, to either of two operative positions ateach of which one of said belts is tightened into driving relationshipwith the pulleys about which it is trained, and the other belt isinoperative.

4. In a power driven hand-guided soil tilling device, the combinationset forth in claim l, further characterized by the fact that: the primemover is an internal combustion engine mounted on the chassis frame at alevel above the rotor, said engine having a shaft, one end portion ofwhich projects from the engine; and further characterized by theprovision of a rotor drive shaft drivingly connected with the rotor andcarried by the chassis frame for rotation on an axis spaced from andparallel to that of the engine shaft; and by the fact that the reversingdrive transmission means comprises a pair of axially adjacent pulleys onthe projecting end portion of the engine shaft, a pair of axiallyadjacent pulleys on the rotor drive shaft, each substantially oppositeone of the pulleys on the engine shaft, a first belt loosely trainedabout one of the pulleys on the engine shaft and one of the pulleys onthe rotor drive shaft with the stretches thereof substantially defininga single loop encircling both of its pulleys, said first belt beingadapted to connect the rotor drive shaft with the engine shaft forrotation therewith in one direction when tightened into drivingengagement with its pulleys, a second belt loosely trained about theremaining pulleys on said shafts but with its stretches crossing oneanother and forming a pair of loops each encircling one of its pulleys,said second belt being adapted to connect the rotor drive shaft with theengine shaft for rotation therewith in the opposite direction whentightened into driving engagement with its pulleys, and by the fact thatsaid shiftable control means comprises a belt tightening device mountedfor movement by the manually operable means in opposite directions froma neutral position to each of two operative positions, said belttightening device including free running idlers cooperable with saidbelts and movable bodily with the belt tightening device to tightenedone or the other of said belts into driving engagement with its pulleys,depending upon the direction in which the belt tightening device ismoved from its neutral position by the manually operable means.

5. In a power driven hand-guided soil tilling device, the combinationset forth in claim l, further characterized by: the fact that the primemover is an internal combustion engine; by the fact that the reversingdrive transmission means comprises a pair of drive pulleys driven inopposite directions by the internal combustion engine, a pair of drivenpulleys drivingly connected with the rotor, a belt looped about one ofsaid drive pulleys and one of the driven pulleys, a second belt loopedabout the other drive pulley and the other driven pulley, both of saidbelts being slack and incapable of transmitting torque when thetransmission means is in neutral; and by the fact that said shiftablecontrol means comprises belt-tightening means for selectively tighteningone or the other of said belts to thereby activate the transmissionmeans to effect forward or retrograde rota.- tion of the rotor.

6. The power driven hand-guided soil tilling device of claim wherein theinternal combustion engine has a pair of power output shafts that rotatein opposite directions, each of which has one of said drive pulleys xcdthereto.

7. The power driven hand-guided soil tilling device of claim 6, whereinone of said shafts is the crankshaft of the engine, and the other is thecam shaft.

8. The power driven hand-guided soil tilling device of claim 7, whereinthe drive pulley which provides the torque for forward rotation of therotor is on the crankshaft.

9. The power driven hand-guided soil tilling device of claim 6, furthercharacterized by: a shallow substantially horizontal housing whichprovides substantially the entire chassis frame; by the fact that theinternal combustion engine is mounted on said housing with its powertake-olf shafts projecting vertically down into the housing with theirrespective drive pulleys inside said housing; and further characterizedby a vertically disposed rotor drive shaft drivingly connected at itslower end with the rotor, and having its upper end portion projectinginto the housing and the driven pulleys iixed thereon.

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